1. Field of the Invention
The invention relates to an arrangement for providing a vehicle with electric energy, wherein the arrangement comprises a receiving device adapted to receive an alternating electromagnetic field and to produce an alternating electric current by magnetic induction. The receiving device comprises at least one phase line and preferably a plurality of phase lines, wherein each phase line is adapted to carry a different one of a plurality of phase currents of the alternating electric current. In addition, the invention relates to a vehicle comprising the arrangement. Furthermore, the invention relates to a system for transferring energy to a vehicle, wherein the system comprises the arrangement, including the receiving device and a primary side conductor assembly (arrangement) adapted to generate an alternating electromagnetic field to be received by the secondary side receiving device. The invention also relates to a method of manufacturing the arrangement and to a method of operating a vehicle by means of a receiving device which receives an alternating electromagnetic field and produces an alternating electric current by magnetic induction.
2. Description of Related Art
The terms “primary side” and “secondary side” are used corresponding to the terminology which is used for transformers. In fact, the electric parts of a system for transferring electric energy from a vehicle track or from a vehicle stop to the vehicle by induction form a kind of transformer. Therefore, one difference compared to a conventional transformer is the fact that the vehicle, and thus the secondary side, can move.
WO 2010/031595 A2 discloses an arrangement for providing a vehicle, in particular a track bound vehicle, with electric energy, wherein the arrangement comprises a receiving device adapted to receive an alternating electromagnetic field and to produce an alternating electric current by electromagnetic induction. The receiving device comprises a plurality of windings and/or coils of electrically conducting material, wherein each winding or coil is adapted to produce a separate phase of the alternating electric current.
Details of a preferred embodiment of the primary side conductor arrangement are described in WO 2010/031595 A2. For example, the current lines of the primary side conductor arrangement may extend along the track or road in a serpentine manner, i.e. some sections of the lines extend transversely to the travel direction and some sections of the lines extend in the direction of travel, thereby connecting the transversely extending sections. In particular, as illustrated in FIG. 5 and FIG. 12 of WO 2010/031595 A2, the primary side conductor arrangement preferably produces a magnetic wave which propagates in the direction of travel or opposite to the direction of travel. The speed of the wave is determined by the distance of the transversely extending sections and by the frequency of the alternating current which is carried by the different phases of the primary side electric conductor arrangement.
As also described by WO 2010/031595 A2, the receiving device can be located at the underside of a vehicle and may be covered by a ferromagnetic body, such as a body in the shape of a slab or plate. A suitable material is ferrite. The body bundles and redirects the field lines of the magnetic field and therefore reduces the field intensity above the body to nearly zero.
However, such a body of ferromagnetic material or, alternatively, a shield of electrically conducting material, cannot reduce the field intensity of the electromagnetic field to zero at locations sideways of the body or shield. In particular, while persons are entering or leaving the vehicle, they might pass the area sideways of the receiving device. Therefore, corresponding limits of the field intensity apply and must not be exceeded.